Romney’s Iowa campaign sent out at least two Iowa mailers (there are multiple versions being sent throughout the state but the campaign would not confirm how many) -- large postcards that seem to attack President Obama rather than any of Romney’s GOP rivals.

Romney, who visited the first-in-the-nation caucus state for the third time in roughly a month last Wednesday, seems to be pushing harder in the state. “It’s up to you, Iowa,” both of Romney’s pieces say.

One Romney postcard, which seems to be aimed at social conservatives, tells voters that Mitt Romney is “the strongest Republican to beat Barack Obama and protect our values.”

The campaign, which opened its official headquarters two weeks ago, was also filming an ad at Romney’s event in Eastern Iowa earlier this month.

NBC News

Ron Paul mailer

Paul’s mailer came in a large manila envelope. It was seven pages long, including a page asking for donations and a copy of his “Plan to Restore America.” He was critical of three GOP rivals in his letter to voters, as well: Rick Perry, Cain and Romney.

“Only one candidate for president will fully balance our budget within three years,” Paul starts in his letter.

Newt Gingrich, now leading in many polls nationally, has not sent out any campaign literature or run any paid advertisements in Iowa as of yet. He is scheduled back in the state Thursday.